Sense amplifier for a ROM having a multilevel memory cell
US5012448A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 15, 1988 |
| Grant date | Apr 30, 1991 |
| Priority date | — |
| Expiry date | Jul 15, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11C2211/5634
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A multilevel sense circuit includes a memory MOSFET having one of at least two different current carrying states and a pair of reference MOSFETs one of which has one of the two current carrying states and the other of which has the other current carrying state. A first current supplying circuit is connected to the memory MOSFET for supplying a predetermined amount of current thereto when the memory MOSFET is activated. A second current supplying circuit is connected to the pair of reference MOSFETs and also to the first current supplying circuit, such that twice the aforementioned predetermined amount of current is supplied to the pair of reference MOSFETs when the memory MOSFET is activated. A multilevel semiconductor memory device includes a MOSFET having a channel whose width is varyingly set by providing a non-inverting region in a selected area of the channel by ion implantation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.